New Delhi: Condemning the "unauthorized surveillance" on its leader Arun Jaitley, BJP on Saturday said it will not take things "lying down" and asked Home Minister Sushilkumar Shinde to clarify on who ordered the collection of his call details.

BJP President Rajnath Singh also termed the issue as "serious" and demanded that all those involved in the incident should be brought to book.

"Further investigations are on. Whoever is involved in such an act should be brought to book. Someone who has dared to get the call details in such an unauthorised way is a serious matter," Singh said.

Party spokesperson Prakash Javadekar said, "BJP condemns this unauthorised surveillance on its leader Arun Jaitley. It is a serious issue. The Home Minister owes an explanation and must come clean as to who ordered the collection of information on call details of Jaitley."

Javadekar alleged that this was not the first time that attempts were made at more than one police stations in Delhi to seek the call details of Jaitley and questioned the government as to who ordered collection of such information.

"Who ordered such collection of call details and on whose orders. We are very serious about raising this issue," he said.

The BJP spokesman also "reminded" the Congress party that these were not the times of emergency that they were indulging in such acts.

"We want to remind the Congress that these are not the days of emergency that you can indulge in such activity. We will not take it lying down," he said.

A Delhi Police constable was arrested on February 14 for allegedly trying to access the call details of the Leader of Opposition in the Rajya Sabha.

The 32-year-old Arvind Dabas was arrested and a probe had been initiated to find out other two people who tried to access the details, police sources said.

Dabas allegedly tried to use the official email ID of an ACP to send a request to a mobile service provider for the call detail records of Jaitley.

Jaitley had not complained in the matter, but the police registered a case a few days ago.

Police launched a probe to ascertain whether any official had sought details about his call records or if it was a case of impersonation.

Reports had it that the nodal officer of a telecom service provider had called the police to inform that they had received a request from the police seeking call detail records of Jaitley.